Infinity Primus 362 Modification?

[Alex2507]

What are you thinking, that it would flatten the Peel N Seal too much?

No, the P&S would allow movement ... but even at work they hire me from the neck down so ...

 

[Alex2507]

I used two pieces of All-Thread and an All-Thread connector ...

... not to be too much of a wisenhimer but I think a single piece of all-thread with nuts and washers would be more stiff. I envision that connector being a source of wiggle.

... maybe now I'll be able to sleep nights.

I just PM'ed nibhaz about finding that insulation ... not that the OP needs it but I sure would like to be able to shop for the best price.

 

[nibhaz]

Sholling,

So I’ve read through this thread and I’m slightly confused. What is you actual goal? Are you trying to reduce cabinet resonance by physically reducing the amount of acoustical energy being transmitted to the cabinet walls, or are trying to absorb energy to prevent it from being reflected back into the cabinet?

It is my simple understanding that these are two complete different beasts and must be approached in different manners.

The foam+MLV that you are getting may be a good material for reducing transmission of energy to the outer cabinet, but it is a less than ideal product for reducing internal reflections.

I will differ to Wmax for the discussion of cabinet resonance, as he is definitely the expert, and I’m merely a neophyte.

But if you are trying to reduce internal reflection I can tell you that, the closed cell foam (CCF) is inferior to fiberglass for sound absorption.

This says it better than I can while at work.


Acoustics:
Because CCF is generally more rigid and dense than fiberglass insulation, it does not absorb sound as well as fiberglass. This
is especially true when one compares noise reduction coefficients and sound transmission classification between the
materials. Laboratory tests performed in reverberant chambers confirm that discharge sound values are several decibels
higher when using CCF than with fiberglass product. See Acoustic Property Comparison chart.

Conclusion:
The use of Closed Cell Foam Insulation in HVAC appliances is a viable alternative to fiberglass insulation. CCF offers
several advantages over fiberglass with regard to moisture absorption and its resistance against microbiological
contamination. It is a superior product in its durability when compared to fiberglass. CCF however does not perform as well
as fiberglass acoustically. If acoustics are not the primary concern on a project then CCF is an acceptable alternative.

Hopefully moisture and durability should not be a concern inside of a speaker cabinet.

 

[nibhaz]

Thanks for the info Alex! I can get my hands on the rigid fiberglass material pretty easily. I am a sales manager for an HVAC company.
Alex you mentioned a trick thread by Rickster71 so I will look around for it if I have some time later. You also mentioned "full width braces with holes drilled in them for a piece of all-thread at the 1/3 and 2/3 points to be snugged up with nuts and washers and then glued" . I am having a hard time visualizing this.
Would I be able to place the braces in without drilling straight through the cabinet?
Regardless, thanks for all your help and direction guys!

Mike

OP

In a confined space such as a speaker cabinet I would definitely focus my energies on trying to locate OC705, or the equivalent from Knauf or Certain Teed. Whichever manufacturer your company works with should make this easy enough.

 

[Rickster71]

... not to be too much of a wisenhimer but

Why stop now?

I think a single piece of all-thread with nuts and washers would be more stiff. I envision that connector being a source of wiggle.... maybe now I'll be able to sleep nights.

How would you get a single piece of rod to expand when you turned it?
I used two pieces of 1/2" thick rod and connector to make a turnbuckle of sorts. The connector is just a threaded sleeve, like a long nut.
http://brackmann.org/berkeley/Jeep/brakes/mikerollins_adjuster.jpg
I then turn it, and it expands, pressing the hockey pucks into the cabinet.

 

[Alex2507]

How would you get a single piece of rod to expand when you turned it?

Nuts on the end of the shaft ... like last night.

Turning the nuts to remove them would lengthen the shaft ... unlike last night.

The nut with a washer would ride the brace (I couldn't bring myself to say wood).

I would count on adhesive to hold it all in place after slight friction was reached ... probably epoxy on the metal parts instead of lock nuts, maybe lock-tight.

Thanks nibhaz. Was it you who helped someone on here find like 5 local sources for the OC 700 series stuff?

... now back to the **** jokes.

 

[gmichael]

Nuts on the end of the shaft ... like last night.

Turning the nuts to remove them would lengthen the shaft ... unlike last night.

The nut with a washer would ride the brace (I couldn't bring myself to say wood).

I would count on adhesive to hold it all in place after slight friction was reached ... probably epoxy on the metal parts instead of lock nuts, maybe lock-tight.

Thanks nibhaz. Was it you who helped someone on here find like 5 local sources for the OC 700 series stuff?

... now back to the **** jokes.

Did I click on the wrong website?

 

[nibhaz]

Thanks nibhaz. Was it you who helped someone on here find like 5 local sources for the OC 700 series stuff?

... now back to the **** jokes.

Yep, that was me. I was trying to steer adk highlander towards DIY panels or Ready Acoustic ReadyBags, instead of ATS Acoustic panels. The ATS stuff is okay, but doesn’t represent the best ROI IMHO.

SPI and Roofing & Insulation Supply/RIS Insulation Supply are my two go-to companies for rigid fiberglass, but since Craig lives in the boondocks, I had to do some extra leg work…err, um work was slow that day

 

[Alex2507]

I had to do some extra leg work…err, um work was slow that day

It took me a couple of years to find the stuff about a mile from my house.
I should have paid you to track it down for me.

 

[lsiberian]

OP

In a confined space such as a speaker cabinet I would definitely focus my energies on trying to locate OC705, or the equivalent from Knauf or Certain Teed. Whichever manufacturer your company works with should make this easy enough.

You can use R11 you won't get the lower stuff as well, but most of the sound will be killed. Ideally you'd use 4" rockwool. But that makes for a mammoth speaker.

Ok it seems some folks here are confused. Peel-n-seal is designed to kill sound transmission in the panels joined to the driver. Think of it as a giant shock absorber. Rockwool is designed to absorb sound waves. This is why all our drills in North Texas are surrounded by a wall of Rockwool. The combination of both work to eliminate the resonance that are audible. Our next step is to brace the internal speaker. Every 3 to 4 inches will push the panel resonance out of the audible range. Once you do all 3 you have a nearly perfect speaker build quality wise. Sounds simpler than it is. Building a speaker with a constraint layer is extremely challenging for me. I imagine it will take a few attempts for me to do it. Now lining with rock wool and bracing are relatively simple. You will need to EQ the speaker after doing these mods. Also adding certain types of material in certain quantities effect the box frequency in ways you may not expect.

Tom Nousaine wrote a paper on the effects of certain low density dampening materials on the Fb.

 

[skers_54]

You can use R11 you won't get the lower stuff as well, but most of the sound will be killed. Ideally you'd use 4" rockwool. But that makes for a mammoth speaker.

Ok it seems some folks here are confused. Peel-n-seal is designed to kill sound transmission in the panels joined to the driver. Think of it as a giant shock absorber. Rockwool is designed to absorb sound waves. This is why all our drills in North Texas are surrounded by a wall of Rockwool. The combination of both work to eliminate the resonance that are audible. Our next step is to brace the internal speaker. Every 3 to 4 inches will push the panel resonance out of the audible range. Once you do all 3 you have a nearly perfect speaker build quality wise. Sounds simpler than it is. Building a speaker with a constraint layer is extremely challenging for me. I imagine it will take a few attempts for me to do it. Now lining with rock wool and bracing are relatively simple. You will need to EQ the speaker after doing these mods. Also adding certain types of material in certain quantities effect the box frequency in ways you may not expect.

Tom Nousaine wrote a paper on the effects of certain low density dampening materials on the Fb.

Doing a constrained layer with Peel n Seal and garage floor epoxy isn't too tough. It's messy and takes a while because you have to wait for it to dry. But it's well worth it. If you're going to do it one on a finished speaker, I'd recommend using some painter's tape to protect the finish. I didn't and now I have some long nights with a toothbrush ahead of me.

 

[lmt9914]

You can use R11 you won't get the lower stuff as well, but most of the sound will be killed. Ideally you'd use 4" rockwool. But that makes for a mammoth speaker.

Ok it seems some folks here are confused. Peel-n-seal is designed to kill sound transmission in the panels joined to the driver. Think of it as a giant shock absorber. Rockwool is designed to absorb sound waves. This is why all our drills in North Texas are surrounded by a wall of Rockwool. The combination of both work to eliminate the resonance that are audible. Our next step is to brace the internal speaker. Every 3 to 4 inches will push the panel resonance out of the audible range. Once you do all 3 you have a nearly perfect speaker build quality wise. Sounds simpler than it is. Building a speaker with a constraint layer is extremely challenging for me. I imagine it will take a few attempts for me to do it. Now lining with rock wool and bracing are relatively simple. You will need to EQ the speaker after doing these mods. Also adding certain types of material in certain quantities effect the box frequency in ways you may not expect.

Tom Nousaine wrote a paper on the effects of certain low density dampening materials on the Fb.

Isiberian,

If I use peel and seal, rock wool and brace the cabinets, say centered every 3" to 4" have I enhanced cabinet so the sound stays true to the engineers intent or have I altered the engineers sound intent altogether?

 

[ribonzz]

It is about 120 x 40 x 40 cm dimension